Peter Blackbird has learned you can't argue with a dog. Messing with homeless people isn't such a smart idea either.

Still, braving the unknown is just part of the territory when your hobby is checking out dead and dying shopping centers.

This is the quest that drives Blackbird, 22, and Brian Florence, 25, to venture forth from their Queensbury, N.Y., hometown in search of adventure and new material for their Web site -- www.deadmalls.com.

The address on the Internet is dedicated to the losers -- the retail developments that may have been successful for decades but ran into trouble when another mall was built too close or the neighborhood changed. The Web site lists information on almost 40 shopping centers, speculation on what changed and even an offer for free advice on redevelopment.

It's a mission for these guys but it must be said that it's also a great excuse for road trips.

"We try to do one every other weekend," said Blackbird. They're running out of places nearby so the trips are taking longer, and they've got to hurry to get back to their real jobs. "It's almost a marathon thing now."

Their most recent haul brought them to Greengate Mall on Route 30 in Hempfield, an enclosed 650,000-square-foot shopping center that opened in 1965 but has declined in recent years. The last anchor, Montgomery Ward, closed last year.

The friends set off around 3 a.m. on a Sunday morning in April, drove all day and reached Greengate after 5 p.m. They spent about an hour driving around the mall, taking pictures and checking out nearby Greensburg.

"I've never seen a mall that old before," said Florence, who sort of got hooked into this by his longtime friend but now finds himself fascinated by the architectural details and the life cycle of shopping centers. The two went to high school together, a few years apart.

After Greengate, they tried to find North Versailles where the once-bustling Eastland Mall has fallen on slower times. Information on the center that was sent in by a contributor is now posted on their site.

Instead, they ended up at Monroeville Mall, checking out a still-viable center built more than three decades ago.

Blackbird always had an interest in malls. It intensified after he helped convert Hills Department Stores into Ames department stores a few years ago. Many were in what he would call dying centers -- places full of empty storefronts.

Florence takes credit for actually getting the project on the Web. "I was the one [who] talked him into getting the domain name."

The site went up in October 2000 and has received 25,000 hits and numerous letters and e-mails since. "There's a lot more people [who] are into this than anyone realized," said Florence, who has a real job taking questions over the telephone about insurance. Blackbird works on an auto Web site for a local dealership.

Limited geographically by their job responsibilities, they're happy to post contributions from people who've sent pictures and descriptions from all over the country. Sometimes it takes awhile to get the information up. The Greengate pictures haven't been posted yet.

An amateur student of retail development, Blackbird has been reading books on edge cities and new urbanism. He quotes a study that predicts more than 200 malls will fail within the next three years. He's bothered that many centers -- usually huge buildings holding prominent locations in their communities -- seem so disposable, often bulldozed to be replaced with big box stores.

"I can see Peter getting concerned about things that become eyesores," said Ken Minges, director of guidance services for the Queensbury school district. Minges hadn't seen the Web site before but remembered Blackbird from his school days as a polite young man who was never timid about taking a stand on social issues.

"Anywhere that there is a dead mall, you definitely find a grass-roots movement to do something about it," said Steven Bodzin, spokesman for the Congress for the New Urbanism, which promotes the cause of restoring existing urban areas and redesigning suburbs in more livable patterns.

In a 2001 study done for the organization, PricewaterhouseCoopers found that while the majority of U.S. malls were healthy, about 7 percent were considered to be failing, with sales below $150 a square foot, while another 12 percent were ranked vulnerable.

The Congress for New Urbanism advocates mixing other elements in with retail -- housing, offices, educational facilities -- so that if one area runs into problems, the others can carry the project through.

For the two friends, there's another angle to their Web documentary. Tearing down malls also tosses away a repository of a community's memories.

"I want to try and preserve what they were," said Blackbird, who concedes he loves the old-style malls that seem dated but were once cool places to hang out. "I'm a product of my generation."

For each center they visit, they try to gather names of stores that had been there and talk to local residents about their memories of the place.

The amateur researchers also have discovered that properties left untended too long can attract others. Since they try to get photos inside when possible, they relate stories of finding homeless people and animals settled in some locations. A friend checking out a mall that had been empty for more than a decade found lots of mold. When security guards tell the guys to leave, they do. The point isn't to get into trouble. It helps that they take Florence's 1994 Chevrolet Caprice, a used police car that still looks respectable.

And they usually make sure there's time to shop for hard-to-find soda brands. Another hobby for Florence is tracking down regional sodas. Apparently, Pittsburgh is on the border of the area where Mr. Pibb soda can be found as well as a market for Cherokee Red soda.